Aromatic Hydrocarbon

Aromaticity is determined based on Hückel's Rule, which states that a molecule is aromatic if it:

• is planar, cyclic, and conjugated.
• has π electrons (where ).

Analyzing the given species:

1. Structure I: Aromatic (benzene-like), planar cyclic conjugated system with 6 π electrons ( ), satisfies Hückel's rule.
2. Structure II: Aromatic, typically represents a planar cyclic conjugated ion (e.g., cyclopentadienyl anion) with 6 π electrons, satisfies Hückel's rule.
3. Structure III: Non-aromatic or antiaromatic (doesn't fulfill Hückel's rule, usually due to non-planarity or not having electrons).
4. Structure IV: Aromatic (likely represents tropylium ion, cycloheptatrienyl cation), planar cyclic conjugated system with 6 π electrons ( ), satisfies Hückel's rule.
5. Structure V: Non-aromatic or antiaromatic, does not fulfill the aromaticity criteria.

Conclusion:

The species that satisfy all conditions for aromaticity (planar, cyclic, conjugated, and having π electrons) are structures I, II, and IV.

Therefore, the correct answer is Option (D): I, II and IV.